Clostridium perfringens

Clostridium perfringens is a Gram-positive, spore forming rod. It is an obligate anaerobe and is non-motile.

Clostridium perfringens causes a mild but common type of food poisoning. Its spores are heat resistant, surviving normal cooking.

It is primarily the formation of enterotoxins that cause the typical symptoms associated with Clostridium perfringens . The toxin is usually formed by the organism once it is in the human intestine and has started to sporulate. Pre-formed toxin in food sometimes occurs but is not usually in sufficient quantities to cause illness. The toxin is not very heat resistant (destroyed by heating at 60C for 10 minutes).

Clostridium perfringens food poisoning typically causes severe abdominal pain and prolific diarrhoea. Sometimes fever, nausea and even vomiting occur. Normally large number of cells need to be ingested to cause illness and recovery is usually rapid (24 - 48 hours). Deaths in elderly and debilitated people have occurred from Clostridium perfringens but are extremely rare.

The spores of Clostridium perfringens are widely spread in soil, dust and marine sediments. The organism is also found in the faeces of many animals, including on occasions man.

Many foods fit for consumption contain low numbers of Clostridium perfringens . The foods are only likely to cause food poisoning if they are held at elevated temperatures for a period of time. Therefore, although the organism has been isolated from a wide range of foods, outbreaks of food poisoning have mainly been traced to cooked meat and poultry dishes and dairy products.

Clostridium perfringens has the ability to grow at high temperatures very rapidly causing problems in foods that are not cooled quickly e.g. meat joints and large meat dishes. Its optimum growth temperature is 43- 45C and at these temperatures the organism has one of the fastest known growth rates for any bacterium. Clostridium perfringens has the potential to grow between the temperature ranges of 15 and 50C.

The vegetative cells of Clostridium perfringens are usually destroyed at temperatures of 60C and above. Spores present in food from the environment can vary considerably in their heat resistance, surviving at temperatures from 95 -100C for periods of up to one hour.